CVE-2026-18149

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 77% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — Patch released this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

A fix is available — apply it.

undici's retry handler can leave an already-exposed response body pending forever. When a server returns a successful response that declares a Content-Length, sends only part of the body, and closes the connection, the retry handler retries the request. If the retry returns a non-retryable status such as 400, the handler forwards that new response downstream and replaces its internal response stream, but the original response body that the application still holds is never ended or destroyed. As a result calls that read that body never settle, and the configured body timeout does not fire because its timer is tied to the connection parser rather than the orphaned body. An attacker-controlled server can trigger this with two short responses without keeping a connection open, and repeated requests accumulate pending promises and streams that can exhaust application concurrency or memory. This affects undici versions from 7.11.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

September 4, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Sep 4, 2026
Patch available. Sources: github.
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html
github Patch Available

undici vulnerable to Denial of Service via orphaned RetryHandler response body · Advisory · nodejs/undici · GitHub

https://github.com/nodejs/undici/security/advisories/GHSA-pmjh-fq2x-6v4x

Vendor Advisories for CVE-2026-18149(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatgrafana12-4-main-12.4.10-0.2.hum12026-09-09redhat
redhatnodejs26-main-26.7.0-1.5.2.hum12026-08-12redhat
redhatnodejs24-main-24.18.1-0.2.2.hum12026-08-12redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
node-undici5.15.0+dfsg1+~cs20.10.9.3-1 ... 8.9.0+dfsg+~cs3.2.0-1 (39 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 19× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-11 15:52 UTCEG score recompute
  2. 2026-09-11 15:52 UTCVendor advisory
  3. 2026-09-11 14:52 UTCEPSS rescore
  4. 2026-09-11 09:36 UTCEPSS rescore
  5. 2026-09-10 17:14 UTCEG score recompute
  6. 2026-09-10 17:14 UTCVendor advisory
  7. 2026-09-10 09:34 UTCEPSS rescore
  8. 2026-09-09 18:33 UTCEG score recompute
  9. 2026-09-09 18:33 UTCVendor advisory
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-08 19:56 UTCVendor advisory
  12. 2026-09-08 13:15 UTCEG score recompute
  13. 2026-09-08 13:15 UTCVendor advisory
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-07 14:37 UTCVendor advisory
  16. 2026-09-06 15:48 UTCEG score recompute
  17. 2026-09-06 15:48 UTCVendor advisory
  18. 2026-09-06 13:47 UTCEPSS rescore
  19. 2026-09-05 17:10 UTCEG score recompute
  20. 2026-09-04 18:33 UTCEG score recompute
  21. 2026-09-04 17:55 UTCEG score recompute
  22. 2026-09-04 17:29 UTCEG score recompute
  23. 2026-09-04 17:29 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18149?
CVE-2026-18149 is a medium vulnerability published on September 4, 2026. undici's retry handler can leave an already-exposed response body pending forever. When a server returns a successful response that declares a Content-Length, sends only part of the body, and closes the connection, the retry handler retries the request. If the retry returns a non-retryable status…
When was CVE-2026-18149 disclosed?
CVE-2026-18149 was first published in the National Vulnerability Database on September 4, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18149 actively exploited?
CVE-2026-18149 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 76.6% of all scored CVEs.
What is the CVSS score of CVE-2026-18149?
CVE-2026-18149 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-18149?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18149, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-18149

Explore →

Is Your Infrastructure Affected by CVE-2026-18149?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs